hippi.c

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/*
 * INET     An implementation of the TCP/IP protocol suite for the LINUX
 *      operating system.  INET is implemented using the  BSD Socket
 *      interface as the means of communication with the user level.
 *
 *      HIPPI-type device handling.
 *
 * Version: @(#)hippi.c 1.0.0   05/29/97
 *
 * Authors: Ross Biro
 *      Fred N. van Kempen, <[email protected]>
 *      Mark Evans, <[email protected]>
 *      Florian  La Roche, <[email protected]>
 *      Alan Cox, <[email protected]>
 *      Jes Sorensen, <[email protected]>
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/hippidevice.h>
#include <linux/skbuff.h>
#include <linux/errno.h>
#include <net/arp.h>
#include <net/sock.h>
#include <asm/uaccess.h>

/*
 * Create the HIPPI MAC header for an arbitrary protocol layer
 *
 * saddr=NULL   means use device source address
 * daddr=NULL   means leave destination address (eg unresolved arp)
 */

static int hippi_header(struct sk_buff *skb, struct net_device *dev,
            unsigned short type,
            const void *daddr, const void *saddr, unsigned int len)
{
    struct hippi_hdr *hip = (struct hippi_hdr *)skb_push(skb, HIPPI_HLEN);
    struct hippi_cb *hcb = (struct hippi_cb *) skb->cb;

    if (!len){
        len = skb->len - HIPPI_HLEN;
        printk("hippi_header(): length not supplied\n");
    }

    /*
     * Due to the stupidity of the little endian byte-order we
     * have to set the fp field this way.
     */
    hip->fp.fixed       = htonl(0x04800018);
    hip->fp.d2_size     = htonl(len + 8);
    hip->le.fc      = 0;
    hip->le.double_wide = 0;    /* only HIPPI 800 for the time being */
    hip->le.message_type    = 0;    /* Data PDU */

    hip->le.dest_addr_type  = 2;    /* 12 bit SC address */
    hip->le.src_addr_type   = 2;    /* 12 bit SC address */

    memcpy(hip->le.src_switch_addr, dev->dev_addr + 3, 3);
    memset(&hip->le.reserved, 0, 16);

    hip->snap.dsap      = HIPPI_EXTENDED_SAP;
    hip->snap.ssap      = HIPPI_EXTENDED_SAP;
    hip->snap.ctrl      = HIPPI_UI_CMD;
    hip->snap.oui[0]    = 0x00;
    hip->snap.oui[1]    = 0x00;
    hip->snap.oui[2]    = 0x00;
    hip->snap.ethertype = htons(type);

    if (daddr)
    {
        memcpy(hip->le.dest_switch_addr, daddr + 3, 3);
        memcpy(&hcb->ifield, daddr + 2, 4);
        return HIPPI_HLEN;
    }
    hcb->ifield = 0;
    return -((int)HIPPI_HLEN);
}


/*
 * Rebuild the HIPPI MAC header. This is called after an ARP has
 * completed on this sk_buff. We now let ARP fill in the other fields.
 */

static int hippi_rebuild_header(struct sk_buff *skb)
{
    struct hippi_hdr *hip = (struct hippi_hdr *)skb->data;

    /*
     * Only IP is currently supported
     */

    if(hip->snap.ethertype != htons(ETH_P_IP))
    {
        printk(KERN_DEBUG "%s: unable to resolve type %X addresses.\n",skb->dev->name,ntohs(hip->snap.ethertype));
        return 0;
    }

    /*
     * We don't support dynamic ARP on HIPPI, but we use the ARP
     * static ARP tables to hold the I-FIELDs.
     */
    return arp_find(hip->le.daddr, skb);
}


/*
 *  Determine the packet's protocol ID.
 */

__be16 hippi_type_trans(struct sk_buff *skb, struct net_device *dev)
{
    struct hippi_hdr *hip;

    /*
     * This is actually wrong ... question is if we really should
     * set the raw address here.
     */
    skb->dev = dev;
    skb_reset_mac_header(skb);
    hip = (struct hippi_hdr *)skb_mac_header(skb);
    skb_pull(skb, HIPPI_HLEN);

    /*
     * No fancy promisc stuff here now.
     */

    return hip->snap.ethertype;
}

EXPORT_SYMBOL(hippi_type_trans);

int hippi_change_mtu(struct net_device *dev, int new_mtu)
{
    /*
     * HIPPI's got these nice large MTUs.
     */
    if ((new_mtu < 68) || (new_mtu > 65280))
        return -EINVAL;
    dev->mtu = new_mtu;
    return 0;
}
EXPORT_SYMBOL(hippi_change_mtu);

/*
 * For HIPPI we will actually use the lower 4 bytes of the hardware
 * address as the I-FIELD rather than the actual hardware address.
 */
int hippi_mac_addr(struct net_device *dev, void *p)
{
    struct sockaddr *addr = p;
    if (netif_running(dev))
        return -EBUSY;
    memcpy(dev->dev_addr, addr->sa_data, dev->addr_len);
    return 0;
}
EXPORT_SYMBOL(hippi_mac_addr);

int hippi_neigh_setup_dev(struct net_device *dev, struct neigh_parms *p)
{
    /* Never send broadcast/multicast ARP messages */
    p->mcast_probes = 0;

    /* In IPv6 unicast probes are valid even on NBMA,
    * because they are encapsulated in normal IPv6 protocol.
    * Should be a generic flag.
    */
    if (p->tbl->family != AF_INET6)
        p->ucast_probes = 0;
    return 0;
}
EXPORT_SYMBOL(hippi_neigh_setup_dev);

static const struct header_ops hippi_header_ops = {
    .create     = hippi_header,
    .rebuild    = hippi_rebuild_header,
};


static void hippi_setup(struct net_device *dev)
{
    dev->header_ops         = &hippi_header_ops;

    /*
     * We don't support HIPPI `ARP' for the time being, and probably
     * never will unless someone else implements it. However we
     * still need a fake ARPHRD to make ifconfig and friends play ball.
     */
    dev->type       = ARPHRD_HIPPI;
    dev->hard_header_len    = HIPPI_HLEN;
    dev->mtu        = 65280;
    dev->addr_len       = HIPPI_ALEN;
    dev->tx_queue_len   = 25 /* 5 */;
    memset(dev->broadcast, 0xFF, HIPPI_ALEN);


    /*
     * HIPPI doesn't support broadcast+multicast and we only use
     * static ARP tables. ARP is disabled by hippi_neigh_setup_dev.
     */
    dev->flags = 0;
}

struct net_device *alloc_hippi_dev(int sizeof_priv)
{
    return alloc_netdev(sizeof_priv, "hip%d", hippi_setup);
}

EXPORT_SYMBOL(alloc_hippi_dev);